Microsoft annoucned today that it has sold 40 million Windows 8 licenses, in the month since launch on October 26. Tami Reller, finance and marketing head of the Windows business, shared this news with industry and financial analysts, investors and media today at the Credit Suisse 2012 Annual Technology Conference.

"The journey is just beginning, but I am pleased to announce today that we have sold 40 million Windows 8 licenses so far," Reller said.

Reller was named as one of two executives to run the Windows unit after president Steven Sinofsky left two weeks ago.

Windows 8 is also outpacing Windows 7 in terms of upgrades, according to Microsoft.

The launch of Windows 8 at the end of October also saw the grand opening of the Windows Store. Microsoft said there were more apps in the Windows Store at launch than any other app store at their launch and since then, the number of apps in the Windows Store has doubled. A number of apps in the Windows Store have crossed the $25,000 revenue mark and the developer keeps 80% of the revenue they make off downloads for the life of their app. New apps added to the Windows Store since launch include CBS, ABC News, ABC Family, Flixster, OWN (Oprah Winfrey Network), Vimeo and Top Gear.